AU3558201A

AU3558201A - Device for injecting a product on a predetermined site of a moving object

Info

Publication number: AU3558201A
Application number: AU35582/01A
Authority: AU
Inventors: Patrick Mie
Original assignee: Sidel SA
Current assignee: Sidel SA
Priority date: 2000-02-16
Filing date: 2001-01-23
Publication date: 2001-08-27
Anticipated expiration: 2021-01-23
Also published as: EP1257371A1; CN1400928A; ATE276837T1; EP1257371B1; BR0108345A; CA2396556C; US6681816B2; FR2804938A1; DE60105765T2; CN1242855C; JP2003522691A; MXPA02007825A; US20030000969A1; WO2001060536A1; FR2804938B1; DE60105765D1; BR0108345B1; CA2396556A1; PT1257371E; JP3650753B2

Abstract

A device for injecting a product towards a predetermined site of objects continuously moving along a given path while being spaced apart from one another by a specific step. The device (10) includes a series of injectors (26) borne by a mobile support (28) while being spaced apart on the support by a pitch corresponding to that of the objects, and the support (28) is driven in a reciprocating movement such that, during a forward phase of the movement, the injectors (26) move each opposite the predetermined site of one of the objects, and in the time interval of the reciprocating movement of the support is equal to the time interval between the passage of two consecutive objects in front of a common fixed point, multiplied by the number of injectors on the support.

Description

WO 01/60536 PCT/FRO 1/00209 Device for Injecting a Product onto a Predetermined Area of a Moving Object 5 This invention relates more particularly to the field of apparatuses for manufacturing and/or processing and/or filling hollow bodies. By way of example, the invention will be described in the context of an apparatus for manufacturing and/or filling thermoplastic containers. More particularly, the device 10 according to the invention will be described in the context of a machine for making polyethylene terephthalate (PET) bottles in which the bottles are obtained by blow moulding a preform produced beforehand by injection moulding. In such apparatuses, it is often necessary at some time or another during the 15 manufacturing, processing or filling procedure, to inject a product into a hollow body. In a unit for making or filling bottles, the said product may for example be a sterilising agent. The said apparatuses generally operate continuously, the hollow bodies all following 20 the same path in the apparatus, being continuously moved one after the other. The said continuous nature of the movement of the hollow bodies presents a problem when it comes to injecting a product such as a sterilising agent inside each hollow body. Recourse is generally had to two solutions. 25 In one solution, the simplest, the product is injected through a fixed nozzle into each hollow body when the hollow body in question passes in front of the nozzle. However, in high-speed apparatuses the time for which each hollow body is opposite the nozzle is greatly reduced. As a result it becomes difficult to spray sufficient quantity of product in good spraying conditions, above all when it is sought to ensure 30 good distribution of the injected product inside the hollow body. Injecting the desired quantity of product then involves increasing the flow rate of the product, detracting from good control of the spray. It is also possible to bring the commencement of WO 01/60536 2 PCT/FRO1/00209 spraying forward and end it later, with the risk that part of the product will not be sprayed inside the hollow body, which entails product wastage and soiling of the outside of the hollow body and the machine. 5 Another solution would be to use a specific machine analogous to a rotary bottle filling machine. However, the cost of such a solution would be much too high. The object of this invention is thus to provide a new design for an injection device which is simple and reliable and allows injection of a product into moving hollow 10 bodies, the conditions under which the product is injected having to be fully controllable. With that object, the invention provides a device for injecting a product in the direction of a predetermined area of objects moving continuously along a given path 15 while being spaced from each other at a predetermined pitch, wherein the device comprises a series of injectors which are carried by a movable support while being spaced on the support at a pitch corresponding to that of the objects, wherein the support is driven with an alternating motion such that during a forward phase of the movement the injectors are each displaced to face the predetermined area of one of the 20 objects, and wherein the period of alternating movement of the support is equal to the time interval between the passing of two consecutive objects before the same fixed point, multiplied by the number of injectors on the support. According to other features of the invention: 25 - during the forward phase of the movement the injectors are displaced in parallel with the objects and at the same speed as the objects; - the alternating movement of the support comprises in addition to the forward phase 30 a return phase during which the movement is in the opposite direction and two turning phases; WO 01/60536 3 PCT/FR01/00209 - the duration of the four movement phases is of the same order of magnitude; - for the full length of the alternating movement the path of the injectors remains 5 parallel to the path of the objects; - the path taken by the injectors is the arc of a circle; - the device comprises a transfer wheel which is made to rotate continuously about its 10 axis on which the objects are loaded along a part of their trajectory, and the injectors follow a path being the arc of a circle about the same axis; - the alternating movement of the movable support is controlled by a system comprising a movable cam and a cam follower connected to the support; 15 - the cam is a rotary cam having a continuous rotary motion; - the cam has a continuous rotary motion about the same axis as the axis of rotation of the support; 20 - the cam has a continuous rotary motion about an axis parallel to the axis of rotation of the support; - the cam takes the form of a plate the contour of which forms the cam track; 25 - the cam follower is pressed against the cam by elastic return means; - the device comprises a second cam with which a second cam follower linked to the support cooperates, and the profiles of the two cams complement each other so as to 30 ensure positive control of the support in both directions of its alternating movement; WO 01/60536 4 PC 1/ KUI/UU2U9 - one at least of the two cam followers comprises elastic means capable of compensating for the geometrical imperfections of the device; - it comprises a plate in which there is formed a slot with two parallel sides in which 5 there circulates a roller which is connected to the support and which is capable of cooperating with each of the two sides of the slot, the said two sides each forming a cam track to ensure positive control of the support in both directions of its travel; - the cam is rotated by the transfer wheel with the interposition of a reduction gear 10 mechanism; - the objects are hollow bodies with an opening; and - the injectors are provided to inject a product inside hollow bodies. 15 Other features and advantages of the invention will appear from a reading of the detailed description hereinbelow as well as from the annexed drawings in which; - figure 1 is an exploded perspective diagrammatic view of the device according to 20 the invention; - figure 2 is a perspective diagrammatic view of the device in figure 1 when it is assembled; 25 - figure 3 is a diagrammatic top view of the device; - figure 4 is a partial view of an axial section ; and - figures 5A to 5 F are schematic diagrams illustrating different successive positions 30 of the device in operation.

WO 01/60536 r'%,ih''XuI uuz-uV The invention will be hereinafter described in the context of a device 10 for injecting a sterilising agent such as hydrogen peroxide (H 2 0 2 ) or peracetic acid (APA) inside preforms 12 intended for the manufacture of PET bottles. The preforms are hollow bodies made by injection moulding. They are in general approximately tubular and 5 present a closed end and an open end. The open end 14, which is designed to form the open neck of the final container, is generally made directly in its final form in the injection mould and comprises for example a thread 16 and an external radial neck ring 18. 10 In numerous bottle-making apparatuses the preforms are transported to the stretch blow moulding machine by a positive transfer system in which the preforms continuously follow a defined path while being spaced apart from each other at a predetermined pitch. The said positive transfer system comprises for example a notched wheel 20 which is rotated continuously about its more or less vertical axis 15 Al. In this instance, the wheel 20 comprises at its circumference 20 semi-circular notches 22, the diameter of the notches 22 being approximately equal to that of the preforms. In a known fashion, the preforms 12 are introduced onto the wheel 20 at a loading 20 point so as each to be received in a notch, and so as to be supported by their neck ring 18 on the wheel 20. Downstream of the loading point, a guide 24 shaped as the arc of a circle with axis Al extends around the wheel 20 to form another support zone for the preforms 12 and to prevent them from escaping the notches 22. Hence, while the preforms 12 are on the wheel 20 they follow a path in the shape of the arc of a circle 25 about axis Al, up to an unloading point where they leave the wheel 20 in order to continue being transferred by other means. In a bottle-making apparatus, such a notched wheel may for example be arranged between a preform feeding device and a thermal conditioning oven in which the 30 preforms are brought to a temperature allowing them to be blow moulded.

WO 01/60536 6 PCT/FRO1/00209 In accordance with the teachings of the invention, the device 10 comprises several injectors 26 which are carried by a movable support 28. In the example shown, the injectors 26 are five in number and are carried by a support 28 in the form of a plate which is movable in rotation about the axis Al and which is arranged above the level 5 of the wheel 20. On support 28 the injectors 26 are arranged in the arc of a circle about the axis Al, the diameter of which corresponds to the diameter of the notched wheel, and are spaced from each other along the said arc by a distance corresponding to the distance separating two consecutive notches 22 of the wheel 221. 10 Hence, by harmonising the relative angular positions of the wheel 20 and the support 28 about the axis Al, the five injectors 26 may inject product into five preforms carried by the wheel 20. According to the invention, the support 28 is controlled to have an alternating rotation 15 movement about axis Al, the control of the moment being such that during at least one phase of the said movement injectors 26 exactly follow the movement of the procession of preforms carried by the wheel 20. In the example shown, the alternating movement of the support 28 is controlled by a 20 two-cam system. Hence, the device comprises a first cam 30 which takes the form of a plate the contour of which forms a cam track. The cam 30 is provided to be rotated about a central axis A2 which in the example shown is parallel to the axis Al but distinct therefrom. The 25 movable support 28 comprises a first cam follower 32 which is for example made in the form of a roller and which is provided to roll on the edge surface of the first cam. The first cam 30 is provided to be rotated by the same shaft 34 as that which drives the notched wheel 20, via a pair of gears 36, 38 which have dimensions such that the 30 cam 30 turns twice as fast about its axis A2 as the wheel 20 about its axis Al, the directions of rotation being opposite. As can be seen in figure 3, the cam 30 is ' Translator's note : Apparently a misprint for '20' (see figures).

WO 01/60536 7 PCT/FRO1/00209 symmetrical about its axis A2 in the sense that two points on the edge of the plate which are diametrically opposed with respect to the axis A2 are equidistant from the axis A2. 5 The cam follower 32 is provided to remain permanently in contact with the cam track formed by the edge of the first cam 30. That can be assured by an elastic return system, for example a spring placed between the movable support 28 and a fixed frame element to force the roller 32 against the cam. 10 In the example shown preference was given to provision of a second cam 40, which is integral with the first cam 30, which has a profile complementing that of the first cam 30, and which is provided to cooperate with a second cam follower 42 linked to the support 28. The second cam 40 is thus also rotated about the axis A2, the profile of the said second cam being itself also symmetrical with respect to the axis A2. 15 Advantageously, to take into account dimensional tolerances relating to the manufacture and assembly of the device, the second cam follower 42 is not connected rigidly to the support 28. Hence the second cam follower 42 is carried at one end by a lever 44 which is mounted in rotation by its other end 46 on the movable support 28. 20 The axis of rotation A3 of the lever 44 with respect to the support 28 is parallel to the axes Al and A2. The lever 44 comprises a projection 50 on which is mounted a stop pin 48 which can slide along its axis A4 with respect to the projection 50. However, the said slidability is limited, and the pin is urged to a rest position by a pile of spring washers 51 of the "Belleville" type. The said pin 48 is designed to come to rest 25 against a thrust surface 52 of the support 28, the said surface being positioned on the support so as to force the second cam follower 42 against the second cam 40. When that occurs, the action of the second cam 40 forces the support 28 in the opposite direction from the first cam 30. Hence, the two cams 30, 40 and the two cam 30 followers 32, 42 are positioned in such a way that they force each other against the cam tracks, in such a way that the angular position of the movable support 28 is always fully defined whatever the angular position of the two cams may be.

WO 01/60536 8 PCT/FKU1/U02U9 The sliding pin 48 and spring washers 51 enable the operating play to be taken up. The two-cam system can also be replaced by a system comprising a single cam in the 5 form of a plate in one surface of which there would be cut a groove in the form of a closed loop. The groove would then comprise two parallel opposing edges making it possible to guide a cam follower linked to the support in both directions of the alternating movement. 10 Similarly, the cams 30, 40 have been chosen with an axis of rotation A2 parallel to but distinct from the axis Al of rotation of the support 28. The said positioning allows use of a particularly simple system for driving the cams. However, as a variant, the choice can be made of using a rotary cam with the same axis Al as the support 28. 15 The operation of the device hereinabove described will now be explained with reference to the diagrams in figures 5A to 5F. These diagrams illustrate the toothed wheel 20 and on that wheel two series 12a and 12b of preforms engaged in consecutive notches 22 of the wheel 20. Naturally, the wheel 20 is rotated 20 continuously about its axis Al, in this instance anticlockwise with respect to figures 5A to 5F. Figure 5A corresponds to an angular position of cams 30, 40 about their axis A2 for which the support is in an extreme position. The said positioning will be 25 characterised as extreme upstream with respect to the direction of rotation of the wheel 20 and thus the direction of procession of the preforms 12 carried on the wheel 20. The said extreme upstream position corresponds to a turning point in the alternating movement of the support 28, with the effect that the velocity of the support at that point is zero. In the said position it can be seen that the first series of preforms 30 12a is offset upstream with respect to the injectors 26 carried by the support. In the position in figure 5B it can be seen that the wheel 20 has pivoted by about 20 degrees in an anticlockwise direction with respect to the extreme upstream position.

WO 01/60536 9 PCT/FRO 1/00209 Because of the arrangement of the gears 36, 38 the cams 30, 40 have turned around axis A2 by an angle twice as great and in the opposite direction. It will be remarked that the two cam followers 32, 42 are both in contact with the cam with which they are respectively associated. In the said position it will be remarked that the five injectors 5 26 carried by the support 28 are exactly above the five preforms 12a in the first series. That means that between the positions in figures 5A and 5B the preforms have "caught up with" the injectors 26. In fact, the said phase of the movement of the support 28 corresponds to a progressive acceleration of the support from zero velocity to an angular speed approximately equal to the speed of the wheel 20. 10 The position of the support shown in figure 5B marks the beginning of a shadowing phase during which for a certain time the wheel 20 and the support 28 have more or less the same speed. In that manner, for the full time of the said movement phase the injectors are displaced in such a way that they remain just above the preforms so as to 15 be able to inject a product therein. The said shadowing phase continues until the position is reached at which shadowing ends, illustrated in figure 5C, in which it can be seen that the injectors 26 are still directly above the preforms 12a, although the said preforms have continued their procession linked with the rotation of wheel 20. 20 The duration of the said shadowing phase can naturally be adjusted according to need by appropriate design for the cams 30, 40. In figure 5D there is illustrated the extreme downstream position of support 28. Between the positions in figures 5C and 5D the support has progressively slowed so 25 that in figure 5D position it has zero velocity. In fact it can be seen that the preforms 12a of the first series are now offset downstream with respect to the series of injectors 26. The said position thus corresponds to a second turning point in the alternating movement of the support 28. 30 Between the figures 5A and the figures 5D it is understood that the support 28 is rotated essentially by virtue of the first cam 30 which tends to push the first cam follower 32 to make the support pivot in an anticlockwise direction.

WO 01/60536 Iu rt i uuuuzuY Starting from the position in figure 5D and proceeding to the figure 5F position, it is the second cam 40 which. via the second cam follower 42, causes the support 28 to return to its extreme downstream position as illustrated in figure 5F. During the 5 return, the support thus undergoes a progressive acceleration followed by a progressive deceleration in order to arrive at its extreme downstream position with zero velocity. At that moment, it is seen that the second series of preforms 12b holds in relation to the support 28 the same position as the preform 12a of the first series in figure 5A. 10 Between the said two positions it is thus seen that the wheel 20 has made a quarter turn, corresponding to five times the angular spacing between two successive notches. In other words, the length of time separating the passing of the support from its figure 5A position to its figure 5F position, which corresponds to a period of alternating 15 movement of the support 28, is therefore equal to the time needed for five preforms to pass in front of a fixed point in their path on the wheel 20. The cams 30,40 have at the same time made a half-turn and by virtue of their profile, which exhibits central symmetry with respect to the axis A2, the operation of the 20 device can then continue analogously to that described hereinabove, the injectors 26 thus having to follow the preform 12b of the second series. By means of the device according to the invention sufficient spraying time is provided without stopping or slowing down the preforms, naturally at the same time 25 processing all preforms. In the example illustrated, the duration of the forward phase of the movement, which corresponds to the possible time for spraying product on the moving objects, only represents about a quarter to a third of the total length of a full movement cycle. 30 Naturally, through appropriate design of the cams, this relation would be easy to vary, but as it stands it allows us to have turning phases which do not subject the support to excessively abrupt variations in speed. That advantage assumes that the length of WO 01/60536 11 PC1/11KUI/UU2U9 time for the forward phases and turning phases of the movement are of the same order of magnitude, that is, the proportion of the duration of the phase to the shortest duration is less than 10. 5 As can be seen, the amplitude of the alternating movement of the support 28 is relatively restricted, with the result that the injectors 26 can be supplied with product from a fixed reservoir connected to the injectors by one or more flexible conduits. Such an arrangement is thus much simpler than if use had to be made of a rotary distributor. 10 The invention has thus been described in the particular context of spraying sterilising product into a preform to be used in making containers. Naturally, the invention will find other applications. Hence, a device incorporating 15 the teachings of the invention can be used for processing other objects such as stoppers. It will be useable in processing other predetermined sites on an object, such as the external threaded part of the neck in the case of a preform or bottle, for example.

Claims

1. A device for injecting a product in the direction of a predetermined area of objects moving continuously along a given path while being spaced from each 5 other at a predetermined pitch, characterised in that the device (10) comprises a series of injectors (26) which are carried by a movable support (28) while being spaced on the support at a pitch corresponding to that of the objects, wherein the support (28) is 10 driven with an alternating motion such that during a forward phase of the movement the injectors (26) are each displaced to face the predetermined area of one of the objects, and wherein the period of alternating movement of the support is equal to the time interval between the passing of two consecutive objects before the same fixed point, multiplied by the number of injectors on 15 the support.

2. A device according to claim 1, wherein during the forward phase of the movement the injectors (26) are displaced in parallel with the objects and at the same speed as the objects. 20

3. A device according to either of claims 1 or 2, wherein the alternating movement of the support (28) comprises in addition to the forward phase a return phase during which the movement is in the opposite direction and two turning phases. 25

4. A device according to claim 3, wherein the duration of the four movement phases is of the same order of magnitude.

5. A device according to any of the foregoing claims, wherein for the full length 30 of the alternating movement the path of the injectors (26) remains parallel to the path of the objects. WO 01/60536 13 PCT/FRO1/00209

6. A device according to claim 5, wherein the path taken by the injectors is the arc of a circle. 5

7. A device according to any of the foregoing claims, wherein the device comprises a transfer wheel (20) which is made to rotate continuously about its axis (Al) on which the objects are loaded along a part of their trajectory, and wherein the injectors (26) follow a path being the arc of a circle about the same axis (Al). 10

8. A device according to any of the foregoing claims, wherein the alternating movement of the movable support (28) is controlled by a system comprising a movable cam (30) and a cam follower (32) connected to the support (28). 15

9. A device according to claims 7 and 8 taken in combination, wherein the cam (30) is a rotary cam having a continuous rotary motion.

10. A device according to claim 9, wherein the cam has a continuous rotary motion about the same axis as the axis of rotation of the support. 20

11. A device according to claim 9, wherein the cam (30) has a continuous rotary motion about an axis (A2) parallel to the axis (Al) of rotation of the support (28). 25

12. A device according to any of claims 9 to 11 wherein the cam (30) takes the form of a plate the contour of which forms the cam track.

13. A device according to claim 12, wherein the cam follower is pressed against the cam by elastic return means. 30

14. A device according to claim 12, wherein the device (10) comprises a second cam (40) with which a second cam follower (42) linked to the support (28) WO 01/60536 14 PCT/FRO1/00209 cooperates, and wherein the profiles of the two cams (20, 40) complement each other so as to ensure positive control of the support (28) in both directions of its alternating movement. 5

15. A device according to claim 14, wherein one at least of the two cam followers (32,42) comprises elastic means (48,50,51) capable of compensating for the geometrical imperfections of the device (10).

16. A device according to claim 12, characterised in that it comprises a plate in 10 which there is formed a slot with two parallel sides in which there circulates a roller which is connected to the support and which is capable of cooperating with each of the two sides of the slot, the said two sides each forming a cam track to ensure positive control of the support in both directions of its travel. 15

17. A device according to any of claims 9 to 16, wherein the cam (30) is rotated by the transfer wheel (20) with the interposition of a reduction gear mechanism (36, 38).

18. A device according to any of the foregoing claims, wherein the objects are 20 hollow bodies with an opening.

19. A device according to claim 18, wherein the injectors are provided to inject a product inside hollow bodies. 25